ESA’s Rosetta probe is getting ready to land on a comet

The European Space Agency’s Rosetta probe has been looping through the Solar System for more than a decade now, but it has almost reached its target — a clump of ice and dust some four kilometers in diameter. In just a few months, the Rosetta probe will be orbiting low over the comet 67P/Churyumov–Gerasimenko to watch as the sun bakes its surface, but that’s not the end of the mission. In November of this year, Rosetta will drop a lander onto the surface of 67P to take a closer look.

The comet has an orbital period of only 6.45 years, but Rosetta was launched way back in 2004 so it could slingshot around the inner solar system and line up for its approach to 67P. The rendezvous was timed so Rosetta would be there just as the comet was warmed by the sun and entered its active phase. The probe awoke from its long slumber in January as it closed on P67, and the comet perked up on May 4. Pretty impressive when you consider this whole thing was set in motion more than 10 years ago.

The ESA probe has an array of instruments (several of which were developed by NASA) that will scan the surface of the comet from inside the corona. This will be the closest a probe has ever gotten to an active comet, and it will stay there for 17 months. Of course, there were distant flybys of Halley’s Comet back in the 80s and NASA’s Deep Impact mission successfully blew a hole in one a few years ago, but this is the best case scenario for learning more about these ancient space glaciers.

Orbiting P67 will already be an amazing achievement, but the landing in November will truly be momentous. The Philae lander will drop down to the surface with its own set of instruments to gather data on the surface composition of P67. ESA scientists designed Philae with harpoons on its landing struts to anchor it to the surface. This is necessary because of the low gravity, but no one is sure what the consistency of the comet will be like. Some think it will be crunchy like permafrost, but other scientists expect rock-hard ice.

The action starts in August, when Rosetta will settle into its low orbit around 67P/Churyumov–Gerasimenko.